Mesostructured manganese oxides for efficient catalytic oxidation of CO, ethylene, and propylene at mild temperatures: Insight into the role of crystalline phases and physico-chemical properties.

Removing pollutants for indoor air purification is a key point to ensure the health and well-being of people in confined environments. This work aims to provide new insight into the development of promising manganese oxide catalysts. The effects of different crystalline phases (MnO 2 and Mn 2 O 3) and the role of redox properties and structural defects were investigated to abate indoor pollutants at mild temperatures. These materials were extensively characterized through complementary techniques and catalytic tests were performed to oxidize 100 ppm of CO, ethylene, or propylene. The most promising catalyst was obtained through solution combustion synthesis, achieving total removal at 118, 222, and 172 °C, respectively, with the highest oxidation rate (2.41, 0.88, and 2.47 μmolg−1s−1) and lowest activation energy (50, 32, and 45 kJmol−1) for the three molecules. The synergy between crystalline phases enhanced the catalytic performance and their distribution in the structure was a crucial parameter affecting the number of structural defects. [Display omitted] • Solution combustion synthesis leads to the formation of highly defective structures. • Uncommon bipyramidal morphology was developed without any surfactants or templates. • Superior enhanced catalytic behavior of MnO 2 compared to Mn 2 O 3. • New insight into the role of De Wolff structural defects in oxidizing CO and VOCs. • Great stability in the presence of moisture and after 8 h under reaction conditions. [ABSTRACT FROM AUTHOR]